Shift-controlling device for shifted materials

ABSTRACT

A device for controlling the shift of materials in an apparatus for shifting heavy materials such as, for instance, a walkingbeam-type slab-heating furnace, wherein the acceleration and deceleration of the parts for shifting the shifted materials are so controlled that they may be stopped in a fixed position at any time in the end part of the said apparatus.

United States Patent Mori et al.

[54] SHIFT-CONTROLLING DEVICE FOR 3,376,486 4/1968 Caputo ..3 1 8/257 SHIFTED MATERIALS 3,465,217 9/1969 Kress 318/603 X 96 h ts ..3 l 8 603 [72] inventors: l-laruki Mori, Kitakyushu; Toshinao 17 9/1 9 on Takahashi, Tokyo; Eisuke Koyama, xanagawakent an of Japan Primary Examiner-Benjamin Dobeck [73] Assignee: Nippon Steel Corporation, Tokyo,'Japan y- Lind & Pollack [22] Filed: Feb. 16, 1970 [21] Appl. No.: 11,384 [57] ABSTRACT A device for controlling the shift of materials in an apparatus [30] Foreign Application Priority Data for shifting heavy materials such as, for instance, a walking- Feb. 21, 1969 Japan ..44/1 3849 beam'typF slab'heafing fummg f accelerati?" deceleration of the parts for shlftlng the sh1fted matenals are 52] us. 01... 318/603, 318/257 89 controlled that y may be pp in a fixed position at 51 1 1m. (:1. ..G05h 19/28 y time in the end P of the said pp [58] Field of Search ..318/603, 282, 257

[56] References Cited 1 Claim, 3 Drawing Figures UNITED STATES PATENTS 3,293,521 12/1966 Vroonhoven ..318/282 X F T I +-A 1 j 6 7 a /1 CR1 CR| CR5 -11 1- I 1: 1'. I-

1 1 CR 9 1 2 r; I m J; B

BE r "+1 1 1 A I 1 1" to m CR3 1 CR3 CR5 1: I 1 4 1 l I I C I r-:: ::L 19. 1 {5 C I" "I I I 1 I I CR4 1l1 1 Pmmanrw 15 1972 3. s43. 14?

SHEET 1 UF 2 FIG! ::- Stopp in 1 I stro e 3 Shifting 2 4 Lifting Lowering 5 Returning A (111-) (11) (TV) t 2 B A8St wp n9 k Z '1 l i 2 (c) \(c) g I i '33 7(Sto ll't \strok) I i (0) pp 9 \fl I in); I l av") \I 1 l l I I l l l i l 1 l l l i J i i I I: 9 Acceleration l0 Constant velocity I ll Deceterotion i2 (Stopping stroke) l3 Shifting stroke INVENTORS Ham/d Mon Tosh/n00 70/(0/703/1/ E/su/re- Ka 0070 ATTORNEY SHIFT-CONTROLLING DEVICE FOR SI-IIFTED MATERIALS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift-controlling device for stopping heavy materials on a movable beam accurately in a fixed position at any time in an apparatus for shifting heavy materials such as, for instance, slabs (this expression should be understood as including also blooms and billets) mounted on the movable beam by the movement of the said moveable beam, particularly, for instance, such an apparatus as a walking-beam-type slab-heating furnace. As an example of a heavy material-shifting apparatus, a walking-beam-type slab-heating furnace will be described. H

2. Description of the Prior Art In general, a walking-beam-type slab-heating furnace, which has fluid cylinders, specifically an oil pressure cylinders, is provided with two sorts of cylinders, i.e., a horizontally reciprocating cylinder and an elevating cylinder. As is shown in FIG. I, a slab 3 mounted on a fixed beam is first lifted through a fixed stroke by means of an elevating cylinder (not illustrated), is then shifted to an outlet end of the beam through a fixed stroke by means of the horizontally reciprocating'cylinder 1 and is then lowered on the fixed beam by the descent of the elevating cylinder. Thereupon, the empty movable beam 2 is returned to the starting position by the retreat of the horizontal cylinder 1. Thus, the slabs can be shifted in turn from the inlet side to the outlet side of the long fixed beam by repeating the above-mentioned operation.

However, in this case there are two requirements to be fulfilled, that is, the operation of the movable beam is to be properly accelerated or decelerated so that no shock is applied to these mechanical devices, and secondly the slab in shifting must be able to be stopped always in a fixed position relative to the slab-extracting equipment on the outlet (extracting port) side of the heating furnace. For this purpose, as is shown in FIG. 2, certain acceleration and deceleration curves are predetermined for the stroke of the horizontally reciprocating cylinder of the movable beam andon the basis thereof a slab-shifting per cycle is repeated. However, in fact, because slabs in the heating furnace have various widths, it is so difficult to stop such slabs in a fixed position,,so that such operation must be carried out exclusively by hand, and yet the expected object often can not be obtained.

SUMMARY OF THE INVENTION In view of such circumstances the present invention seeks to provide a controlling device for accurately achieving a slabstopping position by freely adjusting the accelerating and decelerating patterns of a movable-beam-operating cylinder so that it is at an optimum value.

The device of the present invention is composed of a pulse generator, which issues determined signals based on the accelerating and decelerating patterns of a predetermined cylinder stroke, a pulse counter, which counts the number of pulses from said pulse generator, in accelerating setter and a decelerating setter, which convert the number of pulses of said pulse counter into an electric quantity and a cylinder operator, which operates in response to the electric quantity, obtained from these setters, a material detector installed at a fixed distance from a fixed stopping position and a contact opened and closed by signals from said detector and which is arranged ahead of the above-mentioned pulse counter, and an electric quantity comparing circuit for comparing the electric quantity from the above-mentioned acceleration setter and the electric quantity from the deceleration setter and a contact and reverse contact opened and closed by .signals from said electric quantity comparing circuit and which is arranged after the above-mentioned acceleration setter and'deceleration setter.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a general schematic view of a walking-beam-type heating furnace.

FIG. 2 is a diagram of the relationship of an oil pressure cylinder stroke and the cylinder velocity (voltage) of a movable beam in said heating furnace.

FIG. 3 is a schematic diagram of a movable-beam-controlling device according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention shall be explained in greater detail on the basis of an embodiment of the heating furnace illustrated in the drawing.

First of all, in FIG. I, on the inlet side ofa heating furnace is provided a cylinder I horizontally reciprocating a movable beam 2. Said cylinder I is provided with a pulse generator 4 converting the stroke of said cylinder 1 into pulses.

On the other hand, at the outlet (extracting port) side of the heating furnace is positioned a material detector 5 at a fixed distance from afixed stopping position X. Now, in FIG. 3 is shown a shift-controlling circuit according to the present invention including these elements.

The units of the respective devices are as follows.

Four is a pulse generator. (EA-B are pulse counters. (PA is a counter during the time of the cylinder acceleration. (13B and (DC are counters during the time of the cylinder deceleration. The respective pulse counters proceed in turn from I to N under the effect of the pulse signals of the pulse generator 4.

A, B and C enclosed with respective broken lines are respectively acceleration and deceleration setters. With the progress of the above-mentioned pulse counters (ISA-C, a fixed voltage is fed to operate the horizontally reciprocating cylinder I through a CR filter 6, sen'oamplifier 7, servovalve 8 and servopump 9.

That is to say, during acceleration, with an increase in the number of pulses of the pulse counter A, the output voltage from the acceleration setter A gradually becomes higher until it reaches a maximum at N so that the cylinder velocity will become constant (see II-I in FIG. 2). On the other hand, at the time of the deceleration, on the contrary, with an increase in the numbers of pulses of the pulse counters (EB and (TIC, the output voltages from the deceleration setters B and C gradually become lower.

CR is a relay contact for acceleration, and becomes conductive, when the rising and descending cylinders for the movable skid reach the ends of their strokes, though this is not illustrated.

CR is a relay contact for constant velocity, and becomes conductive when the final pulse N in the acceleration setter A is reached.

CR is a relay-contact for deceleration, and becomes conductive, when the number of pulses issued by the pulse generator 4 for the accomplishment of the predetermined stroke (the end of the constant velocity stage) reaches the predetermined value.

CR is a relay contact conductive after the detector 5 operates until the cylinder 1 stops. I

CR is a relay contact conductive when an exciting coil CR is excited on the basis of a voltage difference in a later described voltage comparing circuit and has a reverse contact CR on the output side of the acceleration setter A and deceleration setter B.

Ten is a voltage comparing circuit comparing the voltage from the acceleration setter A and the voltage from the deceleration setter C with each other. II is a memory circuit. In FIG. 2, the acceleration curve (solid line) on the left side is determined by the acceleration setter A, the velocity in the next constant velocity period "-1 has a value determined by the N th set voltage and the deceleration curve I-IV on the right side is a curve corresponding to the set voltage of the deceleration setter B.

The respective signs shown in said FIG. 2 are as follows:

I is a deceleration stopping order signal by a limit switch (not illustrated) fitted in the cylinder 1.

II is a stopping order signal from the outlet side detector 5 during the constant velocity period.

III is a stopping order signal from the outlet side detector 5 during the acceleration period.

IV is a stopping order signal from the outlet side detector during the deceleration period.

IV represents a velocity (voltage) corresponding to the shifting stroke from the position of receiving the above-mentioned signal IV to the maximum stroke.

IV is a position in which the cylinder 1 (or the shifted material) is to stop in response to the signal IV.

a. is an acceleration pattern set by the controlling counter b. is a deceleration pattern set by the controlling counter c. is a deceleration pattern set by the controlling counter (ICC.

An actual operation using these controlling circuits will be explained in the following.

In FIG. 1 when a slab 3 approaches the extracting port, the material detector 5 provided in a fixed position detects the forward end of the slab and a stopping signal is sent out to the movable beam 2. In this case, as described above, the movable beam 2 must move through a preset stopping stroke previously set to give the least shock within a time as short as possible, and stop accurately in a designated position and lower the slab.

A pulse generator 4 is connected to the movable beam 2, as is shown in FIG. 1, and the operation of each oil pressure cylinder is arranged so as to be controlled on the basis of the said pulse generator 4 so that the movable beam 2 will. have the velocity pattern as shown by the solid line in FIG. 2.

This will now be explained along with the way of determining the velocity pattern.

The velocity pattern differs depending on the furnace and operation conditions, and is adjustable. But, it very seldom occurs that the velocity pattern is altered during the operation, once it is set at the time of trial operation or at the starting time. Thus, the velocity pattern is to be previously determined prior to starting the operation.

At first, the shifting stroke of the moving beam 2 itself or the time of one cycle is determined as follows; the time for which the material is to stay in the furnace is determined from the distance from the inlet to the outlet of the heating furnace, the material heating temperature, the temperature of each zone of the heating furnace and the capacity of the following rolling mill, that is, the extracting cycle of the rolled material. By combining these factors, there are determined from the number of strokesrequired to advance a slab through the entire length of the furnace and the total time, both the length of one stroke of the oil pressure cylinder connected to the movable beam and the shifting time for the material.

For example, one stroke can be ISO to 400 mm. long, the lift can be I00 mm. and the shifting time can be about 4.5 seconds for 400 mm.

Further, at the beginning and end of each cycle, a proper acceleration and deceleration of the velocity must be carried out. Thus, the velocity pattern must be properly set so that, when the material is to be shifted from a fixed skid to the movable skid in case the movable skid rises, or, on the contrary, when the material is to be shifted from a movable skid to the fixed skid in case the movable skid is lowered, the acceleration or deceleration will be gradually made without inflicting shocks on these skids or other machine elements.

In determining the acceleration and deceleration, a conventional method may be adopted, wherein test operations are carried out while providing the skids themselves or other machine elements with a vibration detecting unit to measure actual vibrations and various accelerations and decelerations are tried until such patterns are found in which the vibrations are as small as possible.

In order to obtain the velocity pattern the oil pressure cylinder is usually provided with a variable discharge pump, and the regulation is carried out, resorting to the above-mentioned pulse generator 4 connected to the movable skid 2 as follows: The pulse generator 4 sends certain pulse signals for the movement of the movable skid (for instance, 1 pulse signal for the movement of the movable skid through a distance of 2 mm.).

These pulses are counted by counters (IA-CC and electric signal is fed to a servovalve, which controls the oil pressure cylinder, according to the number of pulses. In this case, if the electric signal fed to the servovalve should be arranged to increase in proportion to the number of pulses (for instance, in relation such as in electric signal x for one pulse as counted, an electric signal 2): for two pulses and an electric signal 3.x for three pulses and so on), the acceleration and deceleration patterns will become linear and fixed, which is undesirable.

Therefore, in order to avoid the above-mentioned defect and to make the acceleration and deceleration patterns those which will cause practically no trouble in the operation of the acceleration and deceleration setters it has been proposed in the present invention to previously set relative values between the electric signal and the number of pulses. For instance, taking the case of acceleration as an example, the relation can be a signal Ix for one pulse, 1.5x for two, 2): for three, 31: for four and 5x for five and so onfThe electric signal fed to the servovalve can thus be adjusted so that curved acceleration and deceleration patterns are obtained. The set values as abovementioned are, of course, to be obtained from data of the already mentioned test operations.

The same system can be used for deceleration. In this way, the acceleration and deceleration patterns for a cylinder stroke can be previously determined.

Now, in FIG. 2, when a stopping signal from the outlet side detector 5 is received at a time between the points I and II in the constant velocity period, the contact C R in FIG. 3 is energized to become conductive so that the oil pressure cylinder will stop at the end of a determined stroke according to the deceleration pattern set by the deceleration setter 8.

Then, if the stopping signal is received at the point lll, i.e., in the acceleration period, the contact CR is energized to become conductive so that the pulse counter C will start counting and, with the advance of the cylinder (the increase of the stroke), the voltage of the acceleration setter A will rise, the voltage of the deceleration setter C will fall and, by the voltage comparing circuit 10, while there is a voltage difference, the output will be continuously developed and, when the voltage difference becomes zero, the coil CR will be excited (that is, at the point P in FIG. 2), the contact CR will be energized to as to become conducting, the reverse contact CR will 'open, and consequently the cylinder 1 will be switched over to the deceleration pattern of the deceleration setter C, will begin to decelerate and will stop in the stopping position. Needless to say, as the deceleration pattern of the deceleration setter C is set exactly the same as the deceleration pattern of the deceleration setter B, the stopping position will be the same at all times.

Now, when a stopping order signal from the material detector 5 is received at the point IV, i.e., in the deceleration period, the slab is stopped once along the ordinary deceleration pattern, is lowered, is stopped at the next cycle and is shifted by the amount the stroke was short so that the slablowering position will be invariable. In this case, too, the operation of the voltage comparing circuit 10 is exactly the same so that, at the point Q in FIG. 2, the cylinder 1 will be switched from the acceleration pattern of the acceleration setter A over to the deceleration pattern of the deceleration setter C and the piston will advance by the amount the stroke was short and will stop.

In this case, the pulse counter C memorizes the number of pulses from the point IV up to the beam stop in the memory device 10 so as to resume the counting in the next cycle.

However, in this case, if the amount the stroke is short is on the order of about 10 mm., it is also possible to cause the stroke of the cylinder 1 to have some correction of its stroke without using the memory device 10 so that the cylinder will be stopped at a determined stopping position in one operation.

Thus, in the velocity control and stopping control of such a movable beam as one, on which a slab of an irregular width is placed in an indefinite position, the slab can always be stopped aways in a fixed position while being decelerated with a determined deceleration pattern, for a stopping signal issued at any time.

In explaining the present invention, in order to make it easy to understand the invention, two deceleration setters B and C having contacts are provided. However, it will that such modifications as omitting a contact and combining the setters into one deceleration setter do not deviate from the scope of the present invention.

Further, though a walking-beam-type heating furnace is described as an example, it is clear that the present invention can be used not only for said heating furnace but also for any shifting device having the same operation.

What is claimed is:

l. A shift controlling device for shifted materials comprising a pulse generator issuing fixed signals based on predetermined accelerating and decelerating patterns for controlling a cylinder stroke, a pulse counter coupled to the pulse generator for counting the number of pulses from said pulse generator, an acceleration setter and deceleration setter coupled to said pulse counter for converting the number of pulses from said pulse counter into an electric quantity, a cylinder operator coupled to and operated in response to the electric quantity obtained from said setters, a material detector arranged at a fixed distance from a fixed stopping position for transmitting a signal when a material being shifted is detected, a contact means coupled to said detector and opened and closed by signals from said detector and being coupled in the input to said pulse counter, an electric quantity comparing circuit coupled to said setters for comparing the electric quantity from the acceleration setter and the electric quantity from the deceleration setter, and further contact means and reverse contact means coupled to said comparing circuit and opened and closed, respectively, by signals from said comparing circuit and being coupled in the output circuits of said acceleration setter and deceleration setter. 

1. A shift controlling device for shifted materials comprising a pulse generator issuing fixed signals based on predetermined accelerating and decelerating patterns for controlling a cylinder stroke, a pulse counter coupled to the pulse generator for counting the number of pulses from said pulse generator, an acceleration setter and deceleration setter coupled to said pulse counter for converting the number of pulses from said pulse counter into an electric quantity, a cylinder operator coupled to and operated in response to the electric quantity obtained from said setters, a material detector arranged at a fixed distance from a fixed stopping position for transmitting a signal when a material being shifted is detected, a contact means coupled to said detector and opened and closed by signals from said detector and being coupled in the input to said pulse counter, an electric quantity comparing circuit coupled to said setters for comparing the electric quantity from the acceleration setter and the electric quantity from the deceleration setter, and further contact means and reverse contact means coupled to said comparing circuit and opened and closed, respectively, by signals from said comparing circuit and being coupled in the output circuits of said acceleration setter and deceleration setter. 